An experimental study has been made of magnetic hysteresis in plastically deformed and annealed gadolinium (Gd) metal as a function of annealing temperature. Seven plastically deformed samples were annealed at temperatures ranging from 155° to 916°C; major and minor magnetic hysteresis loops of these seven samples plus one as‐deformed sample were examined. The results are discussed in terms of the recovery and recrystallization processes. The measurements of magnetic parameters clearly show three distinct regions of behavior, viz., the regions of annealing temperature Ta≪300°C, 300≪Ta≪500°C, and Ta≪500°C. These regions are identified as regions of recovery, recrystallization, and completed recrystallization plus additional grain growth, respectively. Two distinct advantages of the magnetic measurements are (i) using the magnetic measurements, it was found possible to distinguish between metallurgical processes which are not easily detectable using traditional measuring techniques, and (ii) the weak‐field magnetic parameters were found to be extremely sensitive to changes in microstructure resulting from the isochronal anneals. The weak‐field (or Rayleigh) hysteresis‐loop data are analyzed in terms of a spring model of domain‐wall pinning by defects. Good qualitative agreement is found between experimental results and predictions based upon this model.
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